Tesla Motors and SpaceX chief executive Elon Musk has warned of the world developing "seriously dangerous" artificial intelligence in five years' time.

In a comment on the site Edge, part of his comment read: "The pace of progress in artificial intelligence (I'm not referring to narrow AI) is incredibly fast. Unless you have direct exposure to groups like Deepmind, you have no idea how fast-it is growing at a pace close to exponential.

"The risk of something seriously dangerous happening is in the five year timeframe. 10 years at most. This is not a case of crying wolf about something I don't understand."

However, the comment on the website was eventually deleted.

Musk's spokespeople has since confirmed that the comments were authentic but he intended to email it to Edge founder John Brockman, which was not for publication.